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#ifndef RFL_PARSING_VIEWREADER_HPP_
#define RFL_PARSING_VIEWREADER_HPP_
#include <array>
#include <sstream>
#include <string_view>
#include <type_traits>
#include <utility>
#include <vector>
#include "../Result.hpp"
#include "../Tuple.hpp"
#include "../internal/is_array.hpp"
#include "Parser_base.hpp"
#include "schemaful/IsSchemafulReader.hpp"
namespace rfl::parsing {
template <class R, class W, class ViewType, class ProcessorsType>
class ViewReader {
private:
using InputVarType = typename R::InputVarType;
static constexpr size_t size_ = ViewType::size();
public:
ViewReader(const R* _r, ViewType* _view, std::array<bool, size_>* _found,
std::array<bool, size_>* _set, std::vector<Error>* _errors)
: r_(_r), view_(_view), found_(_found), set_(_set), errors_(_errors) {}
~ViewReader() = default;
/// Assigns the parsed version of _var to the field signified by _name, if
/// such a field exists in the underlying view.
void read(const std::string_view& _name, const InputVarType& _var) const {
assign_to_matching_field(*r_, _name, _var, view_, errors_, found_, set_,
std::make_integer_sequence<int, size_>());
}
/// Assigns the parsed version of _var to the field signified by _index, if
/// such a field exists in the underlying view.
/// Note that schemaful formats can assign by index.
void read(const int _index, const InputVarType& _var) const {
assign_to_matching_field(*r_, _index, _var, view_, errors_, found_, set_,
std::make_integer_sequence<int, size_>());
}
private:
template <int i, class FieldType>
static bool is_matching(const int _current_index) {
return _current_index == i;
}
template <int i, class FieldType>
static bool is_matching(const std::string_view& _current_name) {
return _current_name == FieldType::name();
}
template <int i>
static void assign_if_field_matches(const R& _r,
const auto _current_name_or_index,
const auto& _var, auto* _view,
auto* _errors, auto* _found, auto* _set,
bool* _already_assigned) {
using FieldType = tuple_element_t<i, typename ViewType::Fields>;
using OriginalType = typename FieldType::Type;
using T =
std::remove_cvref_t<std::remove_pointer_t<typename FieldType::Type>>;
constexpr auto name = FieldType::name();
if (!(*_already_assigned) && !std::get<i>(*_found) &&
is_matching<i, FieldType>(_current_name_or_index)) {
std::get<i>(*_found) = true;
*_already_assigned = true;
auto res = Parser<R, W, T, ProcessorsType>::read(_r, _var);
if (!res) {
std::stringstream stream;
stream << "Failed to parse field '" << std::string(name)
<< "': " << res.error().what();
_errors->emplace_back(Error(stream.str()));
return;
}
if constexpr (std::is_pointer_v<OriginalType>) {
move_to(rfl::get<i>(*_view), &(*res));
} else {
rfl::get<i>(*_view) = std::move(*res);
}
std::get<i>(*_set) = true;
}
}
template <int _pos>
static void assign_to_extra_fields(const R& _r,
const std::string_view& _current_name,
const auto& _var, auto* _view,
auto* _errors, auto* _found, auto* _set) {
auto* extra_fields = _view->template get<_pos>();
using ExtraFieldsType =
std::remove_cvref_t<std::remove_pointer_t<decltype(extra_fields)>>;
using T = std::remove_cvref_t<
std::remove_pointer_t<typename ExtraFieldsType::Type>>;
if (!std::get<_pos>(*_set)) {
::new (extra_fields) ExtraFieldsType();
std::get<_pos>(*_set) = true;
std::get<_pos>(*_found) = true;
}
auto res = Parser<R, W, T, ProcessorsType>::read(_r, _var);
if (!res) {
std::stringstream stream;
stream << "Failed to parse field '" << _current_name
<< "': " << res.error().what();
_errors->emplace_back(Error(stream.str()));
return;
}
extra_fields->emplace(std::string(_current_name), std::move(*res));
}
template <int... is>
static void assign_to_matching_field(const R& _r,
const auto _current_name_or_index,
const auto& _var, auto* _view,
auto* _errors, auto* _found, auto* _set,
std::integer_sequence<int, is...>) {
bool already_assigned = false;
(assign_if_field_matches<is>(_r, _current_name_or_index, _var, _view,
_errors, _found, _set, &already_assigned),
...);
if constexpr (ViewType::pos_extra_fields() != -1) {
static_assert(!schemaful::IsSchemafulReader<R>,
"rfl::ExtraFields are not supported for schemaful formats, "
"because schemaful formats cannot have extra fields.");
constexpr int pos = ViewType::pos_extra_fields();
if (!already_assigned) {
assign_to_extra_fields<pos>(_r, _current_name_or_index, _var, _view,
_errors, _found, _set);
}
} else if constexpr (ProcessorsType::no_extra_fields_) {
static_assert(
!schemaful::IsSchemafulReader<R>,
"Passing rfl::NoExtraFields to a schemaful format does not make "
"sense, because schemaful formats cannot have extra fields.");
if (!already_assigned) {
std::stringstream stream;
stream << "Value named '" << _current_name_or_index
<< "' not used. Remove the rfl::NoExtraFields processor or add "
"rfl::ExtraFields to avoid this error message.";
_errors->emplace_back(Error(stream.str()));
}
}
}
template <class Target, class Source>
static void move_to(Target* _t, Source* _s) {
if constexpr (std::is_const_v<Target>) {
return move_to(const_cast<std::remove_const_t<Target>*>(_t), _s);
} else if constexpr (!rfl::internal::is_array_v<Source> &&
!std::is_array_v<Target>) {
::new (_t) Target(std::move(*_s));
} else if constexpr (rfl::internal::is_array_v<Source>) {
static_assert(std::is_array_v<Target>,
"Expected target to be a c-array.");
for (size_t i = 0; i < _s->arr_.size(); ++i) {
move_to(&((*_t)[i]), &(_s->arr_[i]));
}
} else {
for (size_t i = 0; i < _s->size(); ++i) {
move_to(&((*_t)[i]), &((*_s)[i]));
}
}
}
private:
/// The underlying reader.
const R* r_;
/// The underlying view.
ViewType* view_;
/// Indicates that a certain field has been found.
std::array<bool, size_>* found_;
/// Indicates that a certain field has been successfully set - necessary,
/// because we have to trigger the destructors manually.
std::array<bool, size_>* set_;
/// Collects any errors we may have come across.
std::vector<Error>* errors_;
};
} // namespace rfl::parsing
#endif
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